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Rock-Paper-Scissors: What can Children's Games Teach us about Biodiversity?

2018-02-23

Data:

23/02/2018

Maeci

Rock-Paper-Scissors: What can Children's Games Teach us about Biodiversity?

A lecture by Professor Stefano Allesina, University of Chicago

The first event of the year in our Café Scientifique Series

Explaining the staggering biodiversity observed in rich ecological communities such as tropical rainforests and coral reefs is one of the main goals of ecology. The large number of species that coexist in these communities is puzzling, in light of the so-called "principle of competitive exclusion": if two species compete for the same resources, then the better competitor will displace the worse competitor. In the Amazon rainforest, however, we can find more than 15,000 species of trees---seemingly competing for the same exact resources.

To make sense of this puzzle we can turn to the children's game "rock-paper-scissors": while for each pair of strategies one displaces the other, the circular nature of the game makes it convenient to play all three strategies with equal probability.

The game can be extended to more than three strategies, and recent results show how they could all coexist indefinitely when the game is played by more than two players. I will show how these results can help explain the stable coexistence of competing species, by illustrating the findings of Allesina & Levine (PNAS, 2011), Levine et al. (Nature 2017) and Grilli et al. (Nature 2017).

Stefano Allesina (born in Carpi, Italy in 1976) is a Professor in the Department of Ecology & Evolution and a Senior Fellow of the Computation Institute at the University of Chicago. He is an external Faculty of the Northwestern Institute on Complex Systems (NICO). In 2005, he received a PhD in Ecology from the University of Parma, Italy. He received the NSF CAREER award in 2012. At the University of Chicago, he directs a laboratory devoted to the development of mathematical, statistical and computational methods for the analysis of ecological systems, with an emphasis on ecological networks and dynamics.